1 Overview

Sample selection protocol:

  1. Stationary and Travelling trips

  2. Complete checklists (report all species)

  3. Drop duplicates from group trips.

  4. Drop trips with 1 bird

  5. Duration between 5-240 mins

Notes:

  1. We select cities first, and then users. This gives us the same users in each pre/post period (in 2020) with the caveat that users mobility is limited to the top X cities.

  2. Few people take stationary trips pre-lockdown.

1.1 Birdwatching Activity Across All Cities and Users

Number of users is the count of unique user ID’s active on a given day.

1.2 Birdwatching Activity 4 Urban Centers

1.3 Top 20 Cities

Subset of top 20 cities in which users meeting participation constraint are present.

Subset of Top 20 Cities where power users present
COUNTY STATE POP_DENSITY
North East Delhi Delhi 36155.226
Central Delhi Delhi 27729.524
East Delhi Delhi 27132.476
Chennai Tamil Nadu 26552.754
Kolkata West Bengal 24306.454
Mumbai Suburban Maharashtra 20979.735
Mumbai Maharashtra 19652.299
West Delhi Delhi 19563.408
Hyderabad Telangana 18171.995
Rangareddy Telangana 18171.995
South Delhi Delhi 11060.441
North Delhi Delhi 8254.038
North West Delhi Delhi 8254.038
New Delhi Delhi 5446.456
South West Delhi Delhi 5446.456
Bangalore Karnataka 4381.398
Haora West Bengal 3306.087
North 24 Parganas West Bengal 2444.988
South 24 Parganas West Bengal 819.474

1.4 Pre-Post Lockdown Statistics

This table shows birdwatching activity among users who took at least 2 trips before and after lockdown. Mar 22 trips are dropped.
All Cities
PREPOST Num. Trips Num. Cities Num. Users Num. Species
Before 8561 269 542 1010
After 14858 167 542 778
Top 20
PREPOST Num. Trips Num. Cities Num. Users Num. Species
Before 1376 19 103 387
After 2699 17 103 284

1.5 Trip Statistics

This table shows trip statistics before and after lockdown among users meeting the participation constraint.

All Cities
PREPOST Trip Length Mean Species Richness Median Species Richness
Before 37.72492 17.09064 13
After 25.90759 13.35947 12
Top 20
PREPOST Trip Length Mean Species Richness Median Species Richness
Before 36.84956 15.58939 11
After 25.71212 12.97925 12

1.6 Marginal Species by city

Marginal species are species observed after lockdown which were not observed before lockdown. To implement: in each city, obtain list of species before and after lockdown observed by users meeting participation cosntraint. Extract species in “after” list not in “before” list.

TAXONOMIC.ORDER COMMON.NAME SCIENTIFIC.NAME COUNTY
11515 falcon sp. Falco sp. Kolkata
7173 white egret sp. Ardea/Egretta/Bubulcus sp. Kolkata
4071 swift sp. Apodidae sp. Kolkata
22694 Blyth’s Reed Warbler Acrocephalus dumetorum Kolkata
9306 Common Kingfisher Alcedo atthis Kolkata
7140 Little Egret Egretta garzetta Kolkata
7689 Shikra Accipiter badius Kolkata
8110 Barn Owl Tyto alba Kolkata
6863 Asian Openbill Anastomus oscitans Kolkata
10734 Fulvous-breasted Woodpecker Dendrocopos macei Kolkata
30542 Paddyfield Pipit Anthus rufulus Kolkata
5341 Gray-headed Swamphen Porphyrio poliocephalus Kolkata
22558 Zitting Cisticola Cisticola juncidis Kolkata
10971 Rufous Woodpecker Micropternus brachyurus Kolkata
30145 Scaly-breasted Munia Lonchura punctulata Kolkata
7398 Oriental Honey-buzzard Pernis ptilorhynchus Kolkata
5274 Eurasian Moorhen Gallinula chloropus Kolkata
20680 Large-billed Crow Corvus macrorhynchos Kolkata
11734 Red-breasted Parakeet Psittacula alexandri Kolkata
28406 Taiga Flycatcher Ficedula albicilla South 24 Parganas
26795 Jungle Myna Acridotheres fuscus South 24 Parganas
23519 Red-whiskered Bulbul Pycnonotus jocosus South 24 Parganas
7689 Shikra Accipiter badius South 24 Parganas
8584 Spotted Owlet Athene brama South 24 Parganas
22694 Blyth’s Reed Warbler Acrocephalus dumetorum South 24 Parganas
11708 Alexandrine Parakeet Psittacula eupatria South 24 Parganas
10971 Rufous Woodpecker Micropternus brachyurus South 24 Parganas
8110 Barn Owl Tyto alba South 24 Parganas
18754 Indian Golden Oriole Oriolus kundoo South 24 Parganas
30131 White-rumped Munia Lonchura striata South 24 Parganas
21611 Bengal Bushlark Mirafra assamica South 24 Parganas
11715 Rose-ringed Parakeet Psittacula krameri West Delhi
25417 Jungle Babbler Turdoides striata West Delhi
2009 Laughing Dove Streptopelia senegalensis West Delhi
24645 Indian White-eye Zosterops palpebrosus West Delhi
19538 Black Drongo Dicrurus macrocercus West Delhi
22366 prinia sp. Prinia sp. West Delhi
7268 Glossy Ibis Plegadis falcinellus Bangalore
466 Indian Spot-billed Duck Anas poecilorhyncha Bangalore
24366 Yellow-eyed Babbler Chrysomma sinense Bangalore
26773 Chestnut-tailed Starling Sturnia malabarica Bangalore
30126 Indian Silverbill Euodice malabarica Bangalore
4071 swift sp. Apodidae sp. Bangalore
7264 heron sp. Ardeidae sp. Bangalore
7319 ibis sp. Threskiornithidae sp. (ibis sp.) Bangalore
3303 Common Hawk-Cuckoo Hierococcyx varius Bangalore
26906 myna/starling sp. Sturnidae sp. Bangalore
12547 parakeet sp. Psittaciformes sp. (parakeet sp.) Bangalore
11708 Alexandrine Parakeet Psittacula eupatria Bangalore
7569 Booted Eagle Hieraaetus pennatus Bangalore
7564 Greater Spotted Eagle Clanga clanga Bangalore
30329 House Sparrow Passer domesticus Bangalore
7398 Oriental Honey-buzzard Pernis ptilorhynchus Bangalore
416 Garganey Spatula querquedula Bangalore
20517 Rufous Treepie Dendrocitta vagabunda Bangalore
3083 Blue-faced Malkoha Phaenicophaeus viridirostris Bangalore
9197 Indian Gray Hornbill Ocyceros birostris Bangalore
28957 flowerpecker sp. Prionochilus/Dicaeum sp. Bangalore
7301 Red-naped Ibis Pseudibis papillosa Bangalore
11012 Black-rumped Flameback Dinopium benghalense Bangalore
1330 Gray Francolin Francolinus pondicerianus Bangalore
27943 Blue-throated Flycatcher Cyornis rubeculoides Bangalore
22366 prinia sp. Prinia sp. Bangalore
27863 Oriental Magpie-Robin Copsychus saularis Bangalore
9785 bee-eater sp. Merops sp. Bangalore
3260 Gray-bellied Cuckoo Cacomantis passerinus Bangalore
7028 cormorant sp. Phalacrocoracidae sp. Bangalore
8078 eagle sp. Accipitridae sp. (eagle sp.) Bangalore
34501 bird sp. Aves sp. Bangalore
23150 Dusky Crag-Martin Ptyonoprogne concolor Bangalore
688 duck sp. Anatinae sp. Bangalore
19565 Black/Ashy Drongo Dicrurus macrocercus/leucophaeus Bangalore
7058 Yellow Bittern Ixobrychus sinensis Bangalore
30126 Indian Silverbill Euodice malabarica Mumbai
27856 Indian Robin Copsychus fulicatus Mumbai
22694 Blyth’s Reed Warbler Acrocephalus dumetorum Mumbai
3023 Greater Coucal Centropus sinensis Mumbai
25417 Jungle Babbler Turdoides striata Mumbai
7868 Black Kite Milvus migrans Mumbai
6979 Indian Cormorant Phalacrocorax fuscicollis Mumbai
7689 Shikra Accipiter badius Mumbai
6863 Asian Openbill Anastomus oscitans Mumbai
5890 Little Stint Calidris minuta Mumbai
24044 Phylloscopus sp. Phylloscopus sp. Mumbai
30522 wagtail sp. Motacilla sp. Mumbai
7880 Brahminy Kite Haliastur indus Mumbai
6956 Little Cormorant Microcarbo niger Mumbai
232 Lesser Whistling-Duck Dendrocygna javanica North 24 Parganas
18851 Ashy Woodswallow Artamus fuscus North 24 Parganas
4010 Little Swift Apus affinis North 24 Parganas
20667 Large-billed Crow Corvus macrorhynchos East Delhi
1139 Indian Peafowl Pavo cristatus East Delhi
26755 Rosy Starling Pastor roseus East Delhi
9753 Green Bee-eater Merops orientalis East Delhi
9474 White-throated Kingfisher Halcyon smyrnensis East Delhi
7301 Red-naped Ibis Pseudibis papillosa East Delhi
23805 Hume’s Warbler Phylloscopus humei East Delhi
26787 Bank Myna Acridotheres ginginianus East Delhi
3023 Greater Coucal Centropus sinensis East Delhi
6965 Great Cormorant Phalacrocorax carbo East Delhi
22267 Gray-breasted Prinia Prinia hodgsonii East Delhi
18754 Indian Golden Oriole Oriolus kundoo East Delhi
30329 House Sparrow Passer domesticus East Delhi
7117 Purple Heron Ardea purpurea East Delhi
7563 Indian Spotted Eagle Clanga hastata East Delhi
466 Indian Spot-billed Duck Anas poecilorhyncha East Delhi
6869 Woolly-necked Stork Ciconia episcopus East Delhi
7175 Indian Pond-Heron Ardeola grayii East Delhi
28408 Red-breasted Flycatcher Ficedula parva East Delhi
7140 Little Egret Egretta garzetta East Delhi
7689 Shikra Accipiter badius East Delhi
4010 Little Swift Apus affinis East Delhi
7100 Gray Heron Ardea cinerea East Delhi
6979 Indian Cormorant Phalacrocorax fuscicollis East Delhi
5972 Green Sandpiper Tringa ochropus East Delhi
34500 passerine sp. Passeriformes sp. East Delhi
4071 swift sp. Apodidae sp. East Delhi
28467 Black Redstart Phoenicurus ochruros East Delhi
7381 Egyptian Vulture Neophron percnopterus East Delhi
7319 ibis sp. Threskiornithidae sp. (ibis sp.) East Delhi
24287 Lesser Whitethroat Sylvia curruca East Delhi
26772 Brahminy Starling Sturnia pagodarum South Delhi
25394 Large Gray Babbler Turdoides malcolmi South Delhi
24645 Indian White-eye Zosterops palpebrosus South Delhi
26755 Rosy Starling Pastor roseus South Delhi
23805 Hume’s Warbler Phylloscopus humei South Delhi
5654 Red-wattled Lapwing Vanellus indicus South Delhi
1139 Indian Peafowl Pavo cristatus South Delhi
27856 Indian Robin Copsychus fulicatus South Delhi
30329 House Sparrow Passer domesticus South Delhi
2004 Spotted Dove Streptopelia chinensis Chennai
29407 sunbird sp. Nectariniidae sp. (sunbird sp.) Chennai
7173 white egret sp. Ardea/Egretta/Bubulcus sp. Chennai
3023 Greater Coucal Centropus sinensis Chennai
8883 owl sp. Strigiformes sp. Chennai
22188 Common Tailorbird Orthotomus sutorius Chennai
7398 Oriental Honey-buzzard Pernis ptilorhynchus Chennai
9774 Blue-tailed Bee-eater Merops philippinus Chennai
27308 Orange-headed Thrush Geokichla citrina Chennai
23596 White-browed Bulbul Pycnonotus luteolus Chennai
6863 Asian Openbill Anastomus oscitans Chennai
22305 Ashy Prinia Prinia socialis Chennai
22322 Plain Prinia Prinia inornata Chennai
9698 Pied Kingfisher Ceryle rudis Chennai
30126 Indian Silverbill Euodice malabarica Chennai
26760 Asian Pied Starling Gracupica contra Chennai
7069 Black Bittern Ixobrychus flavicollis Chennai
30329 House Sparrow Passer domesticus Chennai
30472 Western Yellow Wagtail Motacilla flava Chennai
6510 tern sp. Sterninae sp. Chennai
4071 swift sp. Apodidae sp. Chennai
4010 Little Swift Apus affinis Chennai
3168 Asian Koel Eudynamys scolopaceus South West Delhi
7100 Gray Heron Ardea cinerea South West Delhi
4010 Little Swift Apus affinis South West Delhi
30329 House Sparrow Passer domesticus South West Delhi
466 Indian Spot-billed Duck Anas poecilorhyncha South West Delhi
26787 Bank Myna Acridotheres ginginianus South West Delhi
26755 Rosy Starling Pastor roseus South West Delhi
7301 Red-naped Ibis Pseudibis papillosa South West Delhi
19538 Black Drongo Dicrurus macrocercus South West Delhi
7506 Short-toed Snake-Eagle Circaetus gallicus South West Delhi
6965 Great Cormorant Phalacrocorax carbo South West Delhi
27862 Oriental Magpie-Robin Copsychus saularis South West Delhi
20517 Rufous Treepie Dendrocitta vagabunda South West Delhi
23519 Red-whiskered Bulbul Pycnonotus jocosus South West Delhi
22305 Ashy Prinia Prinia socialis South West Delhi
19650 drongo sp. Dicrurus sp. South West Delhi
7868 Black Kite Milvus migrans South West Delhi
28694 Brown Rock Chat Oenanthe fusca South West Delhi
27969 Tickell’s Blue Flycatcher Cyornis tickelliae Hyderabad
7170 Cattle Egret Bubulcus ibis Hyderabad
28789 Thick-billed Flowerpecker Dicaeum agile Hyderabad
20517 Rufous Treepie Dendrocitta vagabunda Hyderabad
28861 Thick-billed/Pale-billed Flowerpecker Dicaeum agile/erythrorhynchos Hyderabad
23311 swallow sp. Hirundinidae sp. Hyderabad
20667 Large-billed Crow Corvus macrorhynchos Hyderabad
1139 Indian Peafowl Pavo cristatus Hyderabad
23153 Barn Swallow Hirundo rustica Hyderabad
30503 White-browed Wagtail Motacilla maderaspatensis Hyderabad
23150 Dusky Crag-Martin Ptyonoprogne concolor Hyderabad
6481 River Tern Sterna aurantia Hyderabad
3260 Gray-bellied Cuckoo Cacomantis passerinus Hyderabad
11376 Eurasian Kestrel Falco tinnunculus Hyderabad
27856 Indian Robin Copsychus fulicatus Hyderabad
7268 Glossy Ibis Plegadis falcinellus Hyderabad
26755 Rosy Starling Pastor roseus Hyderabad
7175 Indian Pond-Heron Ardeola grayii Hyderabad
12547 parakeet sp. Psittaciformes sp. (parakeet sp.) Hyderabad
30468 Gray Wagtail Motacilla cinerea Hyderabad
11516 diurnal raptor sp. Accipitriformes/Falconiformes sp. Hyderabad
1798 Rock Pigeon Columba livia Hyderabad
30472 Western Yellow Wagtail Motacilla flava Hyderabad
7140 Little Egret Egretta garzetta Hyderabad
9197 Indian Gray Hornbill Ocyceros birostris Hyderabad
27943 Blue-throated Flycatcher Cyornis rubeculoides Haora
23153 Barn Swallow Hirundo rustica Haora
9474 White-throated Kingfisher Halcyon smyrnensis Haora
25417 Jungle Babbler Turdoides striata Haora
27664 Asian Brown Flycatcher Muscicapa dauurica Haora
1968 Eurasian Collared-Dove Streptopelia decaocto Haora
4045 Asian Palm-Swift Cypsiurus balasiensis Haora
23932 Large-billed Leaf Warbler Phylloscopus magnirostris Haora
20680 Large-billed Crow Corvus macrorhynchos Haora
7130 Intermediate Egret Ardea intermedia Haora
7170 Cattle Egret Bubulcus ibis Haora
3023 Greater Coucal Centropus sinensis Haora
23906 Green-crowned Warbler Phylloscopus burkii Haora
23922 Greenish Warbler Phylloscopus trochiloides Haora
20517 Rufous Treepie Dendrocitta vagabunda Haora

2 Event Study

We estimate:

\[ SR_{ijtd} = \sum_{e=-24, e\neq0}^{24} 1(t-LD=e)\beta_{e} + X_{ijdt} + \theta_{i} + \mu_{p} + \gamma_{t} + \epsilon_{ijtd}\] where \(SR_{ijtd}\) is species richness observed by user i on trip j on date t in district d. Each coefficient \(\beta_{e}\) captures species richness relative to the day of lockdown (LD). In the preferred specification, LD = March 24, 2020 and this date is normalized to zero and omitted so that it describes the reference period. If the timing of lockdown is exogenous to pre-period outcomes, then \(\beta_{e}\) should be zero for all \(e<0\). \(\theta_{i}\) is a user fixed effect and controls for ability. \(\mu_{p}\) is a trip type fixed effect for stationary or travelling trips. Since users primarily remain in the same city before and after lockdown, we do not include a district fixed effect. \(\gamma_{t}\) are a set of temporal controls and include date fixed effects and hour fixed effects. \(X_{ijdt}\) is a vector of controls including trip duration and daily precipitation in district d.

2.1 Species Distributions (Bangalore Only)

sample: stationary trips at home in both periods. data: number of times each user sees each species before and after lockdown. interpretation: proportion of user base seeing different frequencies of species.

3 Difference-in-Difference

In this specification, we aim to estimate the difference in species richness per trip before and after lockdown, compared to same difference in 2019. In other words, we subtract the change in 2019 (the counterfactual) from the 2020 lockdown effect to remove other determinants of species richness that are changing during the window.

To do this, we first select 2020 users with at least 2 trips before and after lockdown. Then we select 2019 users with the same criteria, using March 24, 2019 as the threshold date. These are different users but share similar characteristics.

Formally, we specify the following standard DID regression:

\[ SR_{ijdt} = \beta_{1} [Treatment_{t} \times Post_{t}] + \beta_{2} [Treatment_{t}] + \beta_{3}[Post_{t}] + X_{ijdt} + \eta_{it} + \nu_{p} + \mu_{d} + \gamma_{t} + \epsilon_{ijdt} \]

Where \(Treatment_{t}\) is a dummy for the year 2020 and \(Post_{t}\) is a dummy equal to one for observations after March 24th. \(\beta_{1}\) is the coefficient of interest and describes the change in species richness before and after March 19 in 2020 compared to the same difference in 2019. \(\beta_{2}\) describes the difference in the “before” groups (pre-intervention). \(\beta_{3}\) captures the time trend in the control (2019) group. \(X_{ijdt}\) is a vector of controls including trip duration and rainfall. \(\eta_{it}\) is a user-by-year fixed effect \(\mu_{d}\) is a set of city fixed effects and \(\gamma_{t}\) is a set of temporal controls including date and hour fixed effects. \(\nu_{p}\) is trip type fixed effect and controls for the type of trip: stationary or travelling.

Difference-in-Difference Estimates
All Cities Top 20 Top 20 Top 20 Top 20 Top 20
Treat x Post 0.282 1.126** 0.896** 1.592*** 1.187*** 1.474***
(0.205) (0.450) (0.372) (0.426) (0.386) (0.402)
Treatment 0.158 -0.194 -1.193 4.316** -0.594 2.297**
(0.150) (0.331) (1.564) (2.045) (1.144) (0.941)
Post -0.702*** -0.440 -0.737*** -0.668** -0.756*** -0.711**
(0.153) (0.336) (0.276) (0.339) (0.290) (0.302)
Rainfall (mm) -0.026 0.228 0.171 0.214 0.256* 0.276*
(0.027) (0.168) (0.132) (0.135) (0.140) (0.149)
Group Size 0.049** 0.069 -0.023 0.185 -0.012 0.184***
(0.023) (0.059) (0.050) (0.122) (0.051) (0.062)
Duration 0.161*** 0.164*** 0.170*** 0.118*** 0.180*** 0.200***
(0.001) (0.003) (0.004) (0.004) (0.004) (0.005)
Particip. Contstraint None 2 Trips 2 Trips 2 Trips 5 Trips 10 Trips
Home No No No Yes No No
District FE Yes Yes Yes Yes Yes Yes
Trip Type FE Yes Yes Yes Yes Yes Yes
Weekend FE Yes Yes Yes Yes Yes Yes
Hour Fe Yes Yes Yes Yes Yes Yes
User x Year Fe No No Yes Yes Yes Yes
Num.Obs. 39423 6442 6442 3483 5112 4365
R2 0.503 0.515 0.715 0.698 0.694 0.679
* p < 0.1, ** p < 0.05, *** p < 0.01